Solubilizer for synthetic detergent



United States Patent SGLUBHLIZER FUR SYNTHETIC DETE Lee R. ehiltz, Harvey, Ill, and Russell H. Rogers, de-

ceased, late of Pains Park, 111., by Evelyn Rogers, executrix, Palos Park, Ill., assignors to Swift 8: Company,

Chicago, Ill, a corporation of Illinois No Drawing. Filed Mar. 13, 1961, Ser. No. 95,435

(llaims. ((31. 252-137) The present invention relates to improved organic sulfonate detergent compositions, and more specifically to a method for increasing the solubility of organic suifonate detergent compositions in water solution.

Synthetic detergents of the alkyl aryl sulfonate variety have found wide application in the detergent industry. Their ionic stability in the presence of alkaline earth metal ions makes them particularly adaptable for use in the so-calied hard waters commonly encountered in many areas.

While allryl aiyl sulfonates are considered to be ellicient surface-active agents by themselves, it is often found that the detergent action of a given amount of these compounds can be economically extended through the addition of inorganic builderflsalts such as alkali metal chlorides, borates, sulfates, phosphates, and so forth. Since alkyl aryl sulfonates are inherently hygroscopic in nature, the addition of inorganic salts lends further improvement to particulate formulations of these compounds in that the inor anic salts reduce the tendency of the sulfonate compositions to lump and harden into solid masses un er conditions of high humidity.

While alkyl aryl sulfonates in combination with relatively large amounts of builder salts are generally highly regarded in the cleaning industry for their economy and eiliciency, many of them possess the undesirable characteristic of salting the active detergent out of solution when present in the usual deterging concentrations. In addition, it is often found that compounded sulfonate detergents are gather slow to go into solution at normal washing temperatures.

It is therefore an object of this invention to provide a detergent composition having improved solubility in aqueous solution.

It is another object of this invention to provide a means by which detergents of the alkyl aryl sulfonate variety may be rendered more soluble in aqueous solutions.

It is a further object of this invention to provide a built surface-active composition containing alkyl aryl sulfonates that goes rapidly into solution.

It is still another object of this invention to provide a method by which particulate alkyl aryl sulfonate detergent compositions containing substantial portions of inorganic builder salts may be rendered more soluble in aqueous solvents.

It is still a further object of this invention to provide a compounded synthetic detergent composition that remains soluble in aqueous solvents over a wide range of temperatures and concentrations.

These and still further objects of the present invention will become readily apparent to one skilled in the art from the following detailed description of the invention:

in general, the present invention involves the addition of minor quantities of the sodium salts of ethylene diamine tetracetic acid and one or more of the sequestrants selected from a group comprising N,N-di(2 hydroxyethyl) glycine, imino diacetic acid, nitrilo triacetic acid, hydroxyethyl amino diacetic acid, and hydroxyethyl ethylene diamine triacetic acid, to synthetic organic detergent compositions which contain alkyl aryl sulfonates as the active organic detergent ingredient in combination with substantial amounts of inorganic builder salts.

More specificaiiy, this invention contemplates the addition of solubilizing amounts of a mixture of amino compounds which comprises from about 50% to about by weight of the tetrasodium salt of ethylene diamine tetracetic acid and from about 5% to about 50% of one or more members selected from a group comprising the above mentioned sequestrants to mixtures of compounded, i.e., built, synthetic detergents which contain alkyl aryl sulfonates as the major organic surface-active component. In order to produce the desirable solubilizing efiiect, the herein contemplated mixture of amino solubilizing agents is added in quantities in excess of at least about 0.25% by weight based on the combined total weight of the organic and inorganic active ingredients of the compounded detergent composition. While amounts as low as 0.25% will in some cases produce the desired result, the generally preferred range is from about 1% to about 4% by weight of the amino mixture based on the combined weight of the organic sulfonate and inorganic builder components, the upper limit of about 4% being the proportion at which further addition of the solubilizing agents produces a progressively diminishing amount of solubilizing effect, and further addition of the solubilizing agents becomes economically unsound. However, amounts of the amino solubilizing compounds in excess of 4% generally have no detrimental effect on the over-all deter ent composition other than acting as a diluent.

The amino solubilizing agents, i.e., ethylene diamine tetracetic acid tetrasodium and the members of the group of sequestrants consisting of the sodium salts of N,N-di(2 hydroxyethyl) glycine, imino diacetic acid, nitrilo triacetic acid, hydroxyethyl ethylene diamine triacetic acid are individually all well known sequestering or chelating agents as are the others which are sold under the trade name of Versenes along with various other sequestering agents having carbony-methylated amino groups. Various members of the group known as Versenes have previously been added to detergents in very small amounts for purposes of sequestering polyvalent metal ions such as magnesium, calcium, and iron and thereby prevent their precipitation as turbidity from solution in the presence of various inorganic ions. However, in the present invention it has been found that the particular combination of the Versenes with the amino compounds mentioned above, possess the unexpected characteristicof preventing the precipitation and increasing the solubility of the anionic surface-active agent whether or not there is an excessive quantity of soluble inorganic ions. Further, it is significant that these specific combinations of sequestrants are necessary.

While the method by which the aforementioned solubilizing agents produce their unexpected result is not fully understood, it is believed that the solubilizing effect is due possibly to a crystal-inhibiting mechanism. It cannot be attributed to the sequestering of any polyvalent metal ions which might be present. This view is substantiated when it is observed the solubilizing etlect produced by the additive is the same whether the composition is being used in hard or distilled water. It is also observed that any of the agents alone will not produce the same solubilizing result nor will. other well known sequestering agents such as the alkali tripolyphosphates, and hexametaphosphates, saccharic acid, urea, thiourea, and so forth.

The or anic synthetic detergents to which the presently disclosed combination of amino solubilizers are to be added includes primarily the alkyl aryl sulfonates of both the monoand polynuclear aromatic hydrocarbons and their homologs having from 9 to 18 carbon atoms in an alkyl chain, as for example, the alkali metal, ammonium, and amino salts of straight and branch chained nonyl-,

decyl-, dodecyl-, pentadecyl-, hexadecyl-, and octadecyl benzene sulfonic acids, the corresponding alkyl substituted alkali metal, ammonium, and amino toluene sulfonate salts, and alkali metal, ammonium, and amino naphthalene sulfonate salts, and so forth. Of particular N,N-di(2 hydroxyethyl) glycine, imino diacetic acid, ni importance in the practice of the present invention ar trilo triacetic acid, hydroxyethyl ethylene diamine triacethe C C monalkyl benzene sulfonates prepared by tic. acid is used; the fourth column specifies the sulfonate reacting benzene with a long-chain C C aliphatic alcoused; and the succeeding columns define the percentage hol, or with a C -C olefin, produced by cracking petroby weight of the sulfonate and the various inorganic leum hydrocarbon gases and polymerizing the olcfins thus builder salts used. formed, or with an alkyl halide obtained by chlorinating The compositions shown below are preferably competroleum hydrocarbons of the boiling range of kerosene; pounded by first forming an aqueous slurry of the detersulfonating the alkyl benzene compounds with sulfuric gent components using from about 25% to about 50% acid, chlorosulfonic acidor sulfur trioxide, etc.; and neutheir total weight of water, then adding the amino com tralizing the resultant sulfonated product with a base such ponents with continuous agitation until the ingredients as NaOI-I, KOH, Na CO etc. are homogeneously mixed. The resultant aqueous mix- The sulfonates mentioned above may be combined with ture may then be dried in the usual manner, or the mixinorganic builder salts such as sodium sulfate, sodium siliture may be utilized in the slurry form if desired.

Table l Percent Composition of Amino Percent Percent Percent Percent Percent Percent Example Amino Additive Sullonate Sulfo- N212SO4 NaCl NazBio NazSiOa Nagloi Additive nato o. 92% ET, 8% DM Sodium, dodeeyl benzene sultonate 10 2 0.50 85% ET, 15% DM Sodium, dodecyl benzene Sultanate.-. 30 50 10 1.0 75% ET, 25% DM.. Sodium, dodecyl benzene sulfonate 10 2.0 50% ET, 50% DM Sodium, dodecyl benzene sulfonate 90 5 2 2.0 92% ET, 8% DM. Sodium tridecyl benzene sulf0nate 40 50 v10 3.0 02% ET, 8% DM-.. Sodium toluene sulfonate 40 50 10 3.0 92% ET, 8% DM Sodium naphthalene sulfonate--. 40 50 10 2.0 92% ET, 8% DM Sodium dodecyl benzene sulfonate 20 20 2.0 92% ET, 8% DM Potassium dodecyl benzene sullonate 40 50 10 2.0 92% ET, 8% i Potassium dodecyl benzene sulfonate. 30 50 10 2.0 90% ET, 10% IDA Sodium dodeeyl benzene sulionate 40 50 10 2. 0 90% ET, 10% NTA Sodium dodecyl benzene sulfonate 40 2.0 90% ET, 10% HDA Sodium dodecyl benzene sullonate 40 50 10 2.0 90% ET, 10% HEDA- Sodium dodecyl benzene sulf0nate 40 60 cate, potassium sulfate, borax, sodium chloride, the sodium phosphates, such as sodium tripolyphosphate and tetrasodium pyrophosphate, and so forth, in most all practical proportions. For purposes of the present invention the detergent compositions include from about 10% to about 90% and usually about 40% to 60% inorganic salts with the remainder constituting the active organic detergent component. The detergent compositions to which the presently disclosed combination of amino solubilizing agents may be added may also include minor amounts of other well known organic foam builders and emulsifying additives such as fatty alcohols, alkylolamides of fatty acids, and so forth in addition to the alkyl aryl sulfonate present. Additional optional ingredients such as brighteners, protective colloids, abrasives, perfumes etc., do not inhibit the solubilizing action of these amino additives.

The solubilizing compounds are preferably added to an aqueous solurry of the detergent composition. Incorporation in this manner assures their even distribution throughout the mixture. The compounded slurry may then be dried by conventional methods which include drum and spray drying procedures. While the present invention is primarily directed to detergent composition which are ultimately processed to a particulate state, it should be understood the novel combination of solubilizing additives herein contemplated could also be advantageously incorporated in detergent compositions which are delivered to the consumer in slurry or solution form.

The following examples listed in tabular form, wherein all percentages are by weight, illustrate specific formulations of the detergent compositions which are within the intended scope of the present invention. In the table below, the first showsthe example number; the second column gives the total amount of the amino additives added; ethylene diamine tetracetic acid tetrasodium is designated as ET, and the sodium salts of the following sequestrants have the corresponding designations-N,N- di-(Z-hydroxyethyl) glycine is designated as DM, imino diacetic acid is designated as IDA, nitrilo triacetic acid is The above composition may be tested for solubility in the following manner: An amount of the compositions equivalent to 5 grams of solids is dissolved in 95 grams of water heated to a temperature of 150. This solution is then cooled Without shaking to a temperature of F. at which time no precipitation of the detergent ingredients will be observed.

In order to ascertain the effectiveness of the added solubilizing agents detergent compositions similar to those given in Examples l-7, but which did not include the solubilizing agents, were prepared. 5 g. (solids basis) of these products, when dissolved in g. of water and held at F. followed by cooling to 80 F, produced considerable precipitation of the active synthetic detergent ingredient in every instance.

The above specific examples clearly demonstrate the solubilizing effectiveness of the proposed combination of sequesterants when added to detergent compositions containing substantial amounts or organic sulfonate deter -v gents in combination with inorganic builder salts.

Obviously many modifications and variations of the invention as hereinbefore set forth may be made without departing from the spirit and scope thereof, and therefore only such limitations should be imposed as are indicated in the appended claims.

We claim:

, l. A surface active detergent composition, characterized by exhibiting a high degree of Water solubility at effective concentration levels, which comprises: a detergent consisting essentially of an alkyl aryl sulfonate and an inorganic detergency builder salt, and at least 0.25% by weight of a mixture consisting of about 50% to about 95% by weight of ethylene diamine tetraacetic acid tetrasodium and from about 5% to about 50% by weight of the sodium salt of N,N-di(2-hydroxyethyl) glycine.

2. A surface active detergent composition, characterized by exhibiting a high degree of water solubility at deterging concentration levels, which comprises: a detergent consisting essentially of from about 10% to about 90% by weight of an alkyl aryl sulfonate and from about 10% to about 90% of an inorganic detergency builder salt; and at least 0.25% by weight of a mixture consisting of from about 50% to about 95% by weight of ethylene diarnine tetraacetic acid tetrasodium and from about 5% to about 50% by weight of the sodium salt of N,N- di(2-hydroxyethyl) glycine.

3. A surface active detergent composition, characterized by exhibiting a high degree of water solubility at deterging concentration levels, which comprises: from about 96% to about 99.75% by weight of a detergent consisting essentially of an alkyl aryl sulfonate and an inorganic detergency builder salt; and from about 0.25% to about 4% by weight of a mixture consisting of from about 50% to about 95% by weight of ethylene diamine tetraacetic acid tetrasodium and from about 5% to about 50% by weight of the sodium salt of N,N-di(2-hydroxyethyl) glycine.

4. The composition of claim 2 wherein the alkyl aryl sulfonate is selected from the group consisting of alkali metal, ammonium, and amine salts of alkyl substituted 2 benzene, toluene, and naphthalene sultonic acids, said 5 alkyl substituent having from about 9 to about 18 carbon atoms therein, and mixtures thereof.

5. The composition of claim 4 wherein the inorganic detergency builder salts are selected from the group consisting of sodium sulfate, sodium chloride, sodium borate, sodium silicate, sodium phosphate, sodium hexameta phosphate, sodium tripolyphosphate, tetrasodium pyrophosphate, and mixtures thereof.

FOREIGN PATENTS Great Britain Aug. 12, 1959 OTHER REFERENCES Sequestrene (Geigy Industrial Chemicals), New York (1952), pp. 36 and 42. 

1. A SURFACE ACTIVE DETERGENT COMPOSITION, CHARACTERIZED BY EXHIBITING A HIGH DEGREE OF WATER SOLUBILITY AT EFFECTIVE CONCENTRATION LEVELS, WHICH COMPRISES: A DETERGENT CONSISTING ESSENTIALLY OF AN ALKYL ARYL SULFONATE AND AN INORGANIC DETERGENCY BUILDER SALT, AND AT LEAST 0.25% BY WEIGHT OF A MIXTURE CONSISTING OF ABOUT 50% TO ABOUT 95% BY WEIGHT OF ETHYLENE DIAMINE TETRAACETIC ACID TETRASODIUM AND FROM ABOUT 5% TO ABOUT 50% BY WEIGHT OF THE SODIUM SALT OF N,N-DI(2-HYDROXYETHYL) GLYCINE. 